The purpose of the cerebral magnetic resonance imaging (MRI) component of the Cardiovascular Health Study (CHS) is to evaluate cerebral changes detected by MRI and their relationship to stroke, stroke risk factors, other cardiovascular diseases (CVD), CVD risk factors, disability, and health care utilization. A secondary goal is to compare subjects with clinically overt stroke to those with asymptomatic MRI changes to identify risk factors for overt manifestations of cerebrovascular disease. The primary objective of the MRI Reading Center is to develop, implement, and monitor performance of a protocol for the cerebral MRI examinations within CHS. The objectives of this additional component are: 1. To describe the prevalence and distributions of subclinical stroke in a free-living elderly population. 2. to quantify associations between subclinical stroke and cardiovascular risk factors and prior cardiovascular and cerebrovascular disease; 3. to assess the relationships between subclinical stroke and subsequent cardiovascular and cerebrovascular disease; 4. to examine differences between subjects with subclinical stroke and those with symptomatic cerebrovascular disease in regard to risk factors, clinical examination, level of functioning, and mortality; and 5. to characterize the natural history of subclinical stroke and other MRI- detected cerebral changes, and their relationships to institutionalization, health care utilization, and the development of disability.